Week 1- Histology Flashcards
What are the roles of the ovary?
Produce gametes
Produce steroids- mainly oestrogen and progesterone
Describe the structure of the ovary?
Has a medulla and cortex.
Describe the medulla of the ovary?
Forms the core of the organ. Contains loose connective tissue, contorted arteries, veins and lymphatics. Its continuous with the hilum of the organ.
Describe the cortex of the ovary?
Has scattered ovarian follicles in a highly cellular connective tissue stroma. The outer layer of the cortex is a dense connective tissue layer called the tunica albuginea, which is covered by a single layer of cuboidal cells called the germinal epithelium.
Which layer of the ovary forms the white outer layer?
The tunica albuginea
Describe the maturation of the ovary from the primordial follicle to where it is released from the ovary?
Primordial follicle
Primary follicle
Secondary follicle
Mature graafian follicle
What is oogenesis?
Development of oocytes from oogonia.
What is folliculogenesis?
Growth of the follicle, which consists of the oocyte and any associated support cells.
Women lose oogonia and oocytes via what process?
Atresia.
Describe the development of follicles before birth
Before birth, the oocytes undergo meiosis but halt in prophase 1. They will then undergo further meiosis at puberty and will complete meiosis II if they are fertilised.
What will happen if an oocyte fails to associate itself with pregranulosa cells?
It dies.
What happens to the pregranulosa cells if the primordial follicle enters the growth phase?
They are squamous before the growth phase, but become cuboidal after.
How can you distinguish between primary follicles and oocytes?
The presence of cuboidal granulosa cells- termed the zona granulosa.
Describe the cell arrangement around the primary follicle?
Squamous cells have proliferated to form a single layer of cuboidal cells. The cells adjacent to cuboidal cells, particularly closest to the follicle have started to develop. You can start to see the zona pellucida.
What is the theca interna and externa and how is it formed?
What is its function?
The theca interna is formed by differentiation of inner layers of stromal cells.
Goes on to secrete oestrogen precursors which are then converted to oestrogen by granulosa cells.
The theca externa remains fibroblast like.
What is the Antrum? What is it filled with? What layer does it form in?
As the follicle enlarges, a space called the Antrum develops.
Filled with Antrum fluid.
The granulosa layer.
When is it classed a Graafian follicle?
The largest of follicles has a large Antrum,
When does the oocyte complete meiosis I? What occurs after this?
One day before ovulation, the oocyte in the largest Graafian follicle will complete meiosis I. It doesn’t form two identical cells, it forms one large secondary follicle and one polar body.
The secondary oocyte then goes onto the second phase of meiosis but stops at metaphase II.
When will the secondary follicle complete meiosis II? What else is produced in this?
Only completes it if fertilised
A secondary polar body.
What is the follicular stigma?
The place where the follicle bulges against the side of the ovary.
What happens after ovulation in the ovary?
The follicle becomes the corpus luteum. It releases oestrogen and progesterone which help prepare the uterus for implantation.
What happens to the corpus luteum if no implantation occurs?
The corpus luteum becomes the corpus albicans.
What happens to the corpus luteum if implantation occurs?
The placenta secretes HCG which prevents degeneration of the corpus luteum for some time so progesterone levels can be maintained.
What are the projections of the Fallopian tubes called?
Fimbrae.
How does the egg get from the ovary to the uterus?
Ejected from the ovary. Collected by the fimbrae of the Fallopian tubes. Moves down the Fallopian tubes by gentle peristaltic movements and currents created by the ciliated epithelium.
Where does fertilisation usually occur?
In the ampulla of the Fallopian tubes.
What type of epithelium is present in the ampulla of the Fallopian tube?
Simple columnar epithelium with ciliated cells and secretory cells. This is surrounded by smooth muscle.
Describe the structure of the isthmus of the Fallopian tube?
Secretory epithelium with few ciliated cells. 3 layers of smooth muscle.
Describe the structure of the uterus?
Endometrium- inner secretory mucosal layer. Made up of tubular secretory glands embedded in a connective tissue stroma.
Myometrium- 3 layers of smooth muscle combined with collagen and elastic tissue.
Perimetrium- outer visceral layer of loose connective tissue covered by mesothelium.
How can the endometrium be divided? Describe each.
Stratum functionalis- undergoes monthly growth, degeneration and loss
Stratum basalis-reserve tissue that regenerates the functionalis.
What happens to the stratum basalis during the proliferative layer of menstruation?
The stratum basalis proliferates and glands, stroma and vasculature grow- increasing the thickness of the endometrium by reconstituting the stratum functionalis.
What happens to the layers of endometrium during the secretory phase of menstruation?
The glands become coiled with a corkscrew appearance and secrete glycogen.
What happens to the layers of the endometrium during the menstruation phase?
Arterioles in the stratum functionalis undergo constriction, depriving the tissue of blood and causing ischaemia, with resultant tissue breakdown and leakage of blood.
What tissues make up the cervix?
Mostly fibrous connective tissue covered with stratified squamous epithelium on its vaginal surface, transitioning to mucous secreting simple columnar epithelium.
What is the significance of the transition zone in the cervix?
Common site of dysplagia and neoplastic changes leading to cervical carcinoma being commonest in this area.
Describe the structure of the mucous secreting epithelium of the cervix?
Deeply furrowed so looks to form glands.
